Modeling the impacts of corrosion product formation on simultaneous sorption and reductive dehalogenation of organochlorine pesticide aldrin by high carbon iron filings (HCIF)

AbstractThe extensive use of organochlorine pesticides and their persistence in the environment has led to it becoming a major contaminant in the ground water and soil. This study concerns the interaction of organochlorine pesticide, aldrin, with high carbon iron filings (HCIF) and the impact of rusting on the performance of HCIF. Two types of HCIF were invesitagted: fresh (with no oxide coating) and rusted (with Fe(II)/Fe(III) oxide coatings). Substantial partitioning of aqueous-phase aldrin to the fresh HCIF surface was observed and the residual aqueous aldrin underwent slow reductive dehalogenation due to interaction with metallic iron. The overall rate of change of total aldrin concentration with time, i.e. (dCt/dt), can be expressed as a function of aqueous concentration (Ca) as −k1 M (Ca)n, where M is the concentration of HCIF. The values of k1 and n were determined to be 3.45 × 10−3 h−1 g−1 iron L and 3.115 for fresh, and 7.73 × 10−3 h−1 g−1 iron L and 2.572 for rusted HCIF, respectively. Equilibri...